Bone health and diet

Top 5 diet recommendations to lower your risk of Osteoporosis

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Adequate nutrition is important throughout all stages of life, and it couldn’t be more critical in the lead up to, and during menopause.  The risk of osteoporosis starts to increase as oestrogen fluctuates and slowly decreases over time, which plays a role in keeping our bones strong. The average woman loses up to 10% of her bone mass in the first 5 years of post menopause.  Reducing your risk of osteoporosis includes diet and nutrition advice that incorporates what to eat and what to avoid, to give your bones the best chance of remaining strong throughout the second half of your life. Nutrition for bone health is one factor within our control that can make a big difference as to whether we will experience bone fractures later in life or not.

Nutrition to maintain your bone health

Most people have heard or know that calcium and vitamin D are important in maintaining bone health.  There are in fact, another two nutrients that are also important in reducing the risk of osteoporosis, as well as foods to avoid that could increase your risk, as they interfere with nutrient absorption. 

1. Calcium

Calcium is the most abundant mineral in the body, with 99% of it stored in our bones and teeth.  It is required to keep our bones strong and forms part of the structural matrix, and acts as a “calcium bank” to help maintain blood levels, with only 1% circulating in our blood.  Blood calcium helps with maintaining blood pressure, nerve function, blood clotting and healthy muscles and is very tightly regulated.  Dietary calcium is absorbed through the gut with the help of Vitamin D, and the efficiency of calcium absorption is known to decline across the menopause years as the menstrual cycle starts to fluctuate along with oestrogen levels. This results in more calcium being released from the skeleton into the blood to maintain the vital functions that blood calcium regulates.  The bone remodelling cycle is then breaking bone down quicker than rebuilding it, and this is often seen in post menopausal women. 

Dietary sources are always best, but in cases where women have osteopenia or osteoporosis, supplementation with calcium and vitamin D may be necessary.  It is important to discuss this with your doctor before embarking on supplementation.

The levels of calcium required for women 31-50 years is 1000mg/day and for women 51-70 years, it is 1300mg/day.  If you have osteopenia or osteoporosis and you are under 50 years of age, you need an intake of 1300mg/day to maintain adequate levels of calcium.

The best dietary sources of of calcium include:

  • Milk,  yoghurt, cheese and cottage cheese – always choose low fat 
  • Bony fish such as sardines and mackerel
  • Broccoli, cabbage, bok choy, kale
  • Legumes and some nuts
  • Fortified soy drinks and plant based milks
  • Nuts – almonds, sesame seeds
  • Soybeans and tofu

How efficiently calcium is absorbed varies with different food groups, and for people who eat high levels of foods that contain oxalates (spinach, rhubarb, beans) or phytates (seeds, nuts, grains, some raw beans and soy isolates) may have lower absorption rates of calcium from those foods. 

2. Vitamin D

Vitamin D is a fat soluble vitamin, meaning that it is stored in the fat cells, as opposed to water soluble vitamins, such as vitamin C, which are excreted from the body.  Vitamin D regulates the balance of calcium in the blood and the skeleton, by forming part of the structural matrix of bone with calcium, and assists the absorption of calcium in the gut into the bloodstream.  It is also involved in maintaining muscle mass and strength.

There are 2 forms of vitamin D, D2 which is found in some plant foods, and D3, which is produced by exposure to sunlight in the skin, and is found in some animal foods.  It is difficult to meet all of the requirements of vitamin D in foods alone, as 80-90% of our vitamin D comes from sunlight and only 10-20% comes from foods.  This is one vitamin where supplements may be useful, especially in the winter and autumn months of the year when sun exposure is minimal.  

Vitamin D recommendations are for women are:

  • aged 31-50 years, 5 micrograms per day (200IU)
  • women aged 51-70 years, 10 micrograms per day (400IU)
  • women 70 years and older, 15 micrograms per day (600IU)

The increase in recommendations for each age group is due to a decrease in the ability of the skin to synthesise Vitamin D as we age.

Dietary sources of D2 include:

  • Mushrooms (exposed to UV light)
  • Fortified foods – in Australia vitamin D fortification in margarine is mandatory, and voluntary for modified and skim milk, powdered milk, yoghurt and cheese
  • Supplements

Dietary sources of D3 include:

  • Oily fish such salmon, herring and mackerel
  • Fish oil
  • Liver
  • Egg yolk

3. Protein

Proteins are crucial to the structure and function of every cell in our body, including bone cells.  The building blocks of protein, amino acids are involved in the bone remodelling cycle, and protein makes up about 50% of the volume of bone.  The most abundant protein in bone is type 1 collagen, providing the framework, strength and flexibility of bone, in combination with calcium.  Muscles also contain proteins called myosin and actin which are involved in muscle contraction, and muscle strength is imperative for mobility and reducing fracture risk from falls as we age.

Adequate amounts of protein can be achieved from dietary sources, both from animal and plant foods.  Diets that contain the recommended amounts of protein are associated with higher bone mineral density when calcium intake is adequate, whereas, adults who consume lower amounts of protein are at risk of fractures and bone loss.  The Women’s Health Initiative study showed that post menopausal women with higher protein intakes had lower risks of fractures and bone loss.  The key with protein intake in protecting bone loss in the menopausal years is that there is adequate calcium and vitamin D intakes as well.

The recommended intakes of dietary protein are:

Women aged 31-50 years 46g/day (0.75g/kg body weight),  51-70 years 46g/day (0.75g/kg body weight) and >70 years 57g/day (0.94g/kg body weight).

The protein recommendations increase as we age as we are more prone to muscle loss.  

Dietary sources of proteins include:

Animal proteins:

  • Lean meats – beef, lamb, pork, chicken, fish
  • Eggs
  • Dairy – milk, yoghurt, cheese

Plant proteins:

  • Legumes and beans, lentils, tofu, chickpeas
  • Nut butters
  • Nuts and seeds – almonds, pine nuts, cashews, pumpkin seeds, sesame seeds, chia seeds

4. Magnesium

Magnesium has many important functions in the body, including electrolyte balance, metabolism, muscle contractions and maintenance of bones and teeth.  Approximately 60% of magnesium in our body is stored in the bones, where it is involved in the bone remodelling cycle by stimulating the bone building cells (osteoblasts).  Magnesium also helps to strengthen the structure of bones by improving the solubility of phosphorus and calcium, and it is also needed to activate vitamin D synthesis.  Studies have shown a correlation in post menopausal women with low magnesium and osteoporosis.

Therefore, adequate amounts of magnesium are imperative for bone health and preventing osteoporosis, in both peri- and post- menopause women.  The recommended intakes of magnesium for women from 31 years of age onwards is 320mg per day.

The best dietary sources of magnesium include:

  • Most green leafy vegetables
  • Legumes, peas and beans
  • Nuts
  • Shellfish
  • Spices
  • Unrefined cereals

5. Foods to avoid

High Salt Foods

Foods high in salt (sodium chloride) causes your body to lose calcium which can result in bone loss.  High salt foods include processed foods, and adding salt to your cooking and/or meals – try to limit these.  It is recommended in Australia that women aged 18+ aim for no more than 2000mg of salt per day.

Beans and Legumes

Although beans and legumes are high in calcium, protein, magnesium and fibre, they contain substances called phytates which lower the absorption of calcium from these foods.  The phytate level can be reduced by soaking legumes and beans (if purchased dried) for 2-3 hours in water, draining them and then adding fresh water to cook them.

Wheat bran

Wheat bran contains high amounts of phytates which lower calcium absorption but the difference compared to beans and legumes is that consuming 100% wheat bran with other foods will inhibit calcium absorption from those foods.  If taking a calcium supplement, it is recommended to take it within 2-3 hours of eating 100% wheat bran to allow for maximum calcium absorption.

Alcohol

Excessive alcohol intake can lead to bone loss and eventually osteoporosis. In Australia, the guidelines for alcohol consumption for healthy women is no more than 10 standard drinks per week, and no more than 4 standard drinks on any one day.  Aim to keep alcohol consumption to a minimum to reduce your risk of low bone density and osteoporosis, and other alcohol related harm.

Caffeine

Caffeine is found in coffee, tea, soft drinks, energy drinks and chocolate.  It is thought that high intakes over a long period of time can increase your risk of osteoporosis as it promotes calcium loss via the kidneys and urine, which could contribute to bone loss.  Research regarding caffeine consumption guidelines is not clear, but up to 400mg per day seems to be a safe limit (about 4 cups of instant coffee).  

Are you at risk of Osteoporosis, or want to be sure that you are getting enough nutrition to protect your bones?  Book an appointment with me to help you manage your bone health.

References

  1. HealthDirect, Caffeine  https://www.healthdirect.gov.au/caffeine
  2. HealthDirect, Foods high in vitamin D  https://www.healthdirect.gov.au/foods-high-in-vitamin-d
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  4. Healthline, Your 7-Day Osteoporosis Diet Plan   https://www.healthline.com/health/managing-osteoporosis/7-day-osteoporosis-diet-plan#key-nutrients
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  8. National Osteoporosis Foundation, Your guide to a bone healthy diet   https://www.nof.org/healthy-bones-guide-tips/
  9. Nutrient Reference Values for Australia and New Zealand,  Calcium, Vitamin D, Protein, Magnesium  https://www.nrv.gov.au/nutrients/calcium  https://www.nrv.gov.au/nutrients/vitamin-d   https://www.nrv.gov.au/nutrients/protein   https://www.nrv.gov.au/nutrients/magnesium
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